This invention relates to apparatus and methods for spatially directing optical beams containing temporally structured data.
There is an ongoing need for further improvements in the rates at which massive amounts of data can be exchanged between, for example, networked computers and other data-handling devices. With the continuing increase in the number of nodes requiring data interchange capability, and in the growth in complexity of data required by each node, data transmission and processing are being pushed to their technological limits. It is thus vital to identify new technological approaches to network implementation so that further increases in the volume and efficiency of data transmission can be realized.
Transmission and processing of data by optical means has shown promise in possibly achieving technological breakthroughs in the speed and efficiency of data handling. Data transmission by optical fibers is now common. The use of spatial-spectral holographic devices may open the door to optical networks operating at substantially higher performance levels than can be realized using conventional technology. One particular arena in which optical data-handling devices offer promise is in the continuous transmission and processing of large blocks of data (greater than 10 kbytes) at very high rates (10 gigabits per second or higher).
In addition to the foregoing, substantial progress has been realized in optical memories. For example, in our work with time-domain, frequency-selective, optical memories, we found that materials exhibiting intrinsic frequency selectivity can be employed to record both the temporal and the spatial characteristics of incident optical beams. Mossberg, xe2x80x9cTime-domain Frequency-selective Optical Data Storage,xe2x80x9d Optics Lett. 7:77-79 (1982). Our subsequent work demonstrated that the same basic interaction could be employed to perform processing of distinct temporally structured optical beams by convolution and cross correlation. Bai et al., xe2x80x9cReal-time Optical Waveform Convolver/Cross Correlator,xe2x80x9d Appl. Phys. Lett. 45:714-716 (1984); and Babbitt et al., xe2x80x9cMixed Binary Multiplication of Optical Signals by Convolution in an Inhomogeneously Broadened Absorber,xe2x80x9d Appl. Optics 25: 962-965 (1986). In this work, we found that the underlying mechanisms were consistent with operation at ultra-high bandwidths while simultaneously providing relatively large time-bandwidth products. (Because the foregoing references are pertinent to an understanding of the present invention, the references are expressly incorporated herein by reference.)
A body of related experimental and theoretical work has also appeared extending these concepts in a variety of directions. For example, references disclosing data storage and processing with intrinsic frequency,selectivity (i.e., using frequency-selective materials) include: Carlson et al., xe2x80x9cTemporally Programmed Free-induction Decay,xe2x80x9d Phys. Rev. A 30:1572-1574 (1984); Babbitt et al., xe2x80x9cConvolution, Correlation, and Storage of Optical Data in Inhomogeneously Broadened Absorbing Materials,xe2x80x9d Proceedings of SPIExe2x80x94The International Society For Optical Engineering, Vol. 639 Advances in Optical Information Processing II, pp. 240-247 (1986); Szabo, U.S. Pat. No. 3,896,420 (Jul.22, 1975); Castro et al., U.S. Pat. No. 4,101,976 (Jul.18, 1978); Burland, U.S. Pat. No. 4,158,890 (Jun.19, 1979); Mossberg, U.S. Pat. No. 4,459,682 (Jul.10, 1984); Mossberg et al., U.S. Pat. No. 4,670,854 (Jun.2, 1987); Babbitt et al., U.S. Patent. No. 5,239,548 (Aug.24, 1993); and Mossberg, U.S. Pat. No. 5,276,637 (Jan.4, 1994). (Because these references are pertinent to an understanding of the present invention, the references are expressly incorporated herein by reference.)
Analogous optical functions have also been realized using frequency-selective spatial gratings in materials that possess no intrinsic frequency selectivity. Mazurenko, xe2x80x9cInterference of Spectrally Dispersed Light,xe2x80x9d Opt. Spectrosc. (USSR) 56:357 (1984); Mazurenko, xe2x80x9cReconstruction of a Nonstationary Wave Field by Holography in a 3-D Medium,xe2x80x9d Opt. Spectrosc. (USSR) 57:343-344 (1984); Mazurenko, xe2x80x9cReconstruction of a Time-Varying Wavefront by Multibeam Interference,xe2x80x9d Sov. Tech. Phys. Lett. 10:228-229 (1984); Mazurenko, xe2x80x9cHolography of Wave Packets,xe2x80x9d Appl. Phys. B 50:101-114 (1990); and Brady et al., xe2x80x9cVolume Holographic Pulse Shaping,xe2x80x9d Optics Lett. 17:610-612 (1992). (Because these references are pertinent to an understanding of the present invention, they are expressly incorporated herein by reference.)
Optical processes responsible for storage and/or processing of temporal waveform data frequently can also lead to the storage of spatial waveform information. For example, sequences of images can be stored and recalled. Mossberg, U.S. Pat. No. 5,276,637.
Notwithstanding the foregoing developments in the prior art, there is a need for devices and methods that permit optical data routing. In particular, there is a need for such devices that can perform passive routing of data at high speed.